Stereoselective synthesis of 3,4-disubstituted and 3,4,5-trisubstituted piperidines by Lewis acid-catalysed ene cyclisation of 4-aza-1,7-dienes
作者:Stephen M. Walker、Jodi T. Williams、Alexander G. Russell、Benson M. Kariuki、John S. Snaith
DOI:10.1039/b708139a
日期:——
there was a fine balance between the desired ene cyclisation and the competing hetero-Diels-Alder reaction, with the product distribution being influenced by the activating group on the enophile, the nature of the ene component, and the Lewis acid used. Activation of the enophile with an oxazolidinone function facilitated Lewis acid-catalysedcyclisation to afford mixtures of ene and hetero-Diels-Alder
Asymmetric Diels–Alder reactions of N-allenoyloxazolidinones catalyzed by Cu(II)–bis(oxazoline) complexes
作者:Torsak Luanphaisarnnont
DOI:10.1016/j.tetlet.2014.10.051
日期:2014.12
Catalytic asymmetric Diels–Alder reactions of N-allenoyloxazolidinones were investigated. Various chiral metal–bis(oxazoline) and metal–pyridinebis(oxazoline) complexes were screened. Cu(SbF6)2(H2O)2(t-BuBox) was found to be the most effective catalyst, giving the product in high yield, enantioselectivity, and endo:exo selectivity. The relative reactivity between N-allenoyloxazolidinones and N-alkenoyloxazolidinones
An efficient catalytic asymmetric [2+2] cycloadditionreaction of allenyl imide and alkenes was achieved by utilizing chiral N,N′-dioxide-magnesium(II) complex as the catalyst. This protocol provided a series of axially chiral cyclobutenes in high yields with excellent enantioselectivities. A stepwise mechanism was proposed based on experimental studies and DFT calculations and π–π stacking interaction
Synthesis of 3,4-disubstituted piperidines by ene cyclisation of 4-aza-1,7-dienes
作者:Stephen M. Walker、Jodi T. Williams、Alexander G. Russell、John S. Snaith
DOI:10.1016/j.tetlet.2005.08.002
日期:2005.9
Ene cyclisation of a variety of 4-aza-1,7-dienes affords 3,4-disubstituted piperidines. In particular, cyclisation of diesters 14 and 20 catalysed by MeAlCl2 gives the corresponding trans 3,4-disubstituted piperidines with diastereomeric ratios of > 200:1. (c) 2005 Elsevier Ltd. All rights reserved.
Narasaka, Koichi; Hayashi, Yujiro; Shimada, Satoru, Israel Journal of Chemistry, 1991, vol. 31, # 3, p. 261 - 271
作者:Narasaka, Koichi、Hayashi, Yujiro、Shimada, Satoru、Yamada, Jun